JP5242842B1 - Wireless communication device - Google Patents

Abstract

A wireless transmission device that does not use an antenna switch module is provided.
A PA that amplifies a transmission signal, a transmission circuit that processes the amplified transmission signal, an antenna, a reception circuit that processes a reception signal received by the antenna, and an LNA that amplifies the reception signal. And the control unit 10e that exclusively activates the PA 31 and the LNA 36. When the control unit 10e activates the PA 31, the transmission circuit 37 matches the impedances of the transmission circuit 37 and the antenna 13, and deactivates the PA 31. When the control circuit 10e activates the LNA 36, the receiving circuit 38 matches the impedances of the receiving circuit 38 and the antenna 13 so that the LNA 36 is turned off. When activated, the impedance seen by the receiving circuit 38 from the antenna 13 is high impedance. To dance state.
[Selection] Figure 4

Description

  The present invention relates to a wireless communication device such as a cordless telephone, a PHS (Personal Handy-phone System), a WLAN (Wireless Local Area Network), and a portable information terminal having a wireless transmission / reception function.

  2. Description of the Related Art Conventionally, a cordless telephone that transmits and receives audio signals and data bidirectionally between a parent device and a child device is known. As a front-end module of such a wireless communication device, a transmission circuit connected to a power amplifier (PA) and a reception circuit connected to a low noise amplifier (LNA) are provided, and an antenna is connected to these transmission / reception circuits. A configuration is known in which switching is performed in a time-sharing manner using an antenna switch module (ASM) (Patent Document 1). In a conventional wireless communication apparatus, transmission and reception can be performed substantially simultaneously by switching the antenna switch module at high speed.

  However, since this antenna switch module consumes several tens of percent of power when in use, an attempt to enable transmission / reception without using an antenna switch module from the viewpoint of power consumption reduction and cost reduction by reducing the number of components. For example, the output of the power amplifier is disconnected from both the power line and the ground at the time of reception and the output terminal of the power amplifier is placed in a high impedance state (Patent Document 2), or between the power amplifier and the antenna. By providing the first phase line and the second phase line between the antenna and the low-noise amplifier, when the power of the power amplifier is shut off, the impedance of the power amplifier viewed from the antenna is almost open. When the power supply of the low noise amplifier is cut off, the impedance of the low noise amplifier viewed from the antenna Substantially left open technique (Patent Document 3) discloses a.

JP 2002-290257 A JP 2007-028459 A JP 2004-343517 A

  However, in the configuration disclosed in Patent Document 2, the antenna switch module itself is removed, but instead of the antenna switch module, a switch for separating the output end of the power amplifier from both the power line and the ground is introduced. In the first place, the switch remains as a result despite the time-division drive that exclusively controls ON and OFF of the transmission circuit and the reception circuit.

  In Patent Document 2, although the output terminal of the power amplifier is in a high impedance state, a transmission impedance conversion circuit is provided between the antenna and the power amplifier, and a signal received by the antenna at the time of reception is converted to transmission impedance. It is configured to flow into the circuit. In other words, the configuration disclosed in Patent Document 2 is merely for setting the output end of the power amplifier in a high impedance state, and the impedance of the transmission circuit (here, the transmission impedance conversion circuit) when viewed from the antenna is in the high impedance state. It is not something to be done.

  For this reason, there are problems such as an increase in power consumption by operating the remaining switches, an increase in the number of parts or circuit scale due to the presence of some switching circuit, and a deterioration in characteristics during reception.

  Further, Patent Document 3 states that by adding a phase line, when a power amplifier or a low noise amplifier is activated / deactivated, the impedance can be changed between a matching state and a high impedance state. However, according to Patent Document 3, it is necessary to satisfy specific preconditions in order to exhibit such an effect. That is, when deactivated, the power amplifier requires only a substantially pure reactance component in the transmission band, and requires that the reflection coefficient be 0.8 or more. As described above, the technique disclosed in Patent Document 3 has a problem in versatility in that applicable power amplifiers and low noise amplifiers are limited.

  The present invention has been devised to solve such problems of the prior art, and its main purpose is to remove the antenna switch module from the wireless communication device to achieve power consumption reduction and cost reduction, In addition, it is an object of the present invention to provide a radio communication apparatus that can realize the transmission characteristics and the reception characteristics without being deteriorated even if the antenna switch module is removed, and without depending on the characteristics of the power amplifier and the low noise amplifier. .

A wireless communication device of the present invention includes a first amplifier that amplifies a transmission signal, a transmission circuit that processes the transmission signal amplified by the first amplifier, an antenna that transmits the transmission signal processed by the transmission circuit, A reception circuit that processes a reception signal received by the antenna, a second amplifier that amplifies the reception signal processed by the reception circuit, and a control that activates the first amplifier and the second amplifier alternately and exclusively. A ZonT impedance when the transmission unit is viewed from the antenna when the control unit is activating the first amplifier, and when the control unit is deactivating the first amplifier The impedance when the transmission circuit is viewed from the antenna is ZoffT, and the reception circuit is viewed from the antenna when the control unit is activating the second amplifier. When the impedance is ZoffR when the impedance is viewed from the antenna when the control unit deactivates the second amplifier, the transmission circuit has a voltage reflection coefficient Γ of the ZonT. A first impedance matching circuit for transitioning the ZonT and the ZoffT so that the absolute value of the voltage reflection coefficient Γ of the ZoffT is increased, and a first impedance matching circuit for transitioning the ZoffT to a high impedance state. A phase adjusting circuit, and the receiving circuit is configured such that the ZonR and the ZonR and the ZonR and the ZonR and the ZonR and the Zoff A second impedance matching circuit for transitioning ZoffR, and transitioning the ZoffT to a high impedance state And a second phase adjustment circuit .

  According to the present invention, the above configuration eliminates the antenna switch module from the components of the wireless communication device without depending on the characteristics of the power amplifier and the low noise amplifier and without degrading the transmission characteristics and the reception characteristics. Reduction of power consumption and cost can be achieved.

(A) Whole perspective view of the main | base station of the radio | wireless communication apparatus of 1st Embodiment, (b) is whole perspective view of the subunit | mobile_unit of a radio | wireless communication apparatus. The block block diagram which shows the outline of the main | base station of a radio | wireless communication apparatus The block block diagram which shows the outline of the subunit | mobile_unit of a radio | wireless communication apparatus Block configuration diagram showing the outline of the amplifier module and radio unit provided in the signal processing unit Configuration diagram showing specific configuration of transmission circuit and reception circuit Explanatory drawing showing a state where the transmitter circuit and receiver circuit are mounted on the substrate Explanatory drawing showing the actual dimensions (dimensions) on the board of the transmitter and receiver circuit Explanatory drawing showing a state where the signal processing unit and its peripheral circuits are mounted on the substrate (A)-(d) is explanatory drawing of the structure which shields a transmission circuit and a receiving circuit, (e) is explanatory drawing which shows the structure of a multilayer substrate. (A) is a block diagram which shows the structure of a 1st phase adjustment circuit, (b) is explanatory drawing of the equivalent circuit of a 1st phase adjustment circuit (A)-(d) Explanatory drawing which shows the locus | trajectory of the impedance on a Smith chart when the parameter of the element which comprises a high frequency circuit changes Block diagram schematically showing the transmitter circuit Explanatory drawing which shows the measurement impedance in the output of PA when PA is activated (ON) and deactivated (OFF) Explanatory drawing explaining the impedance change by transmission line LI1, LI2 when PA is activated (ON) and deactivated (OFF) Explanatory drawing which shows the impedance change of the output of the 1st impedance matching circuit when PA is activated (ON) and deactivated (OFF) Explanatory drawing which shows the impedance change of the output of the 1st balun when PA is activated (ON) and deactivated (OFF) Explanatory drawing which shows the impedance change of the output of the 1st phase adjustment circuit when PA is activated (ON) and deactivated (OFF) (A) is explanatory drawing which shows the state of the impedance seen from the antenna when PA is activated, (b) is explanatory drawing which shows the state of the impedance seen from the antenna when LNA is activated (A) is explanatory drawing explaining a high impedance state on a Smith chart, (b) is explanatory drawing which shows the current flow in a high impedance state, (c) is an equivalent circuit of FIG.19 (b). Graph showing the relationship between the input impedance and total loss of the receiving circuit when PA is activated and LNA is deactivated

A first invention made to solve the above-described problems is a first amplifier that amplifies a transmission signal, a transmission circuit that processes the transmission signal amplified by the first amplifier, and a transmission processed by the transmission circuit. An antenna that transmits a signal, a reception circuit that processes a reception signal received by the antenna, a second amplifier that amplifies the reception signal processed by the reception circuit, and the first amplifier and the second amplifier are alternately and A control unit that activates exclusively, ZonT represents an impedance when the transmission unit is viewed from the antenna when the control unit is activating the first amplifier, and the control unit controls the first amplifier. The impedance when the transmission circuit is viewed from the antenna when inactive is ZoffT, and the antenna when the control unit is activating the second amplifier. When ZonR is an impedance viewed from the receiving circuit and ZoffR is an impedance viewed from the antenna when the control unit is deactivating the second amplifier, the transmitting circuit is the ZonT A first impedance matching circuit that makes the ZonT and the ZoffT transition so that the voltage reflection coefficient Γ of the ZoffT becomes close to 0 and the absolute value of the voltage reflection coefficient Γ of the ZoffT increases. A first phase adjusting circuit for transitioning to an impedance state, wherein the receiving circuit is configured such that the voltage reflection coefficient Γ of the ZonR is close to 0 and the absolute value of the voltage reflection coefficient Γ of the ZoffR is increased. In addition, a second impedance matching circuit for making a transition between the ZonR and the ZoffR, and the ZoffT And a second phase adjustment circuit for making a transition to the impedance state .

  This eliminates the antenna switch module from the components of the wireless communication device and does not depend on the characteristics of the power amplifier or low-noise amplifier, and does not deteriorate the transmission characteristics and reception characteristics, thereby reducing power consumption and costs. can do.

In the second invention, the first impedance matching circuit includes a first capacitor,
One end of the first capacitor is connected between the first amplifier and the first phase adjustment circuit, and the other end of the first capacitor is grounded .

According to a third aspect of the present invention, the second impedance matching circuit includes a second capacitor,
One end of the second capacitor is connected between the second amplifier and the second phase adjustment circuit, and the other end of the second capacitor is grounded .

A fourth aspect of the present invention is pre-Symbol first phase adjustment circuit, ZoffT> so that 2 × ZonT, changing the phase of the transmission signal, the second phase adjustment circuit, ZoffR> and 2 × ZonR Thus, the phase of the received signal is changed.

  Accordingly, it is possible to prevent a transmission signal from flowing into the reception circuit during transmission or a reception signal from flowing into the transmission circuit during reception without providing an antenna switch module.

According to a fifth aspect of the present invention, when the wavelength of a transmission signal in the transmission circuit is λg, the first phase adjustment circuit changes the phase of the transmission signal to be larger than ½λg.

  As a result, the first phase adjustment circuit included in the transmission circuit can be used not only for phase adjustment but also as a high-performance filter.

According to a sixth aspect of the present invention, an inductor and a capacitor constituting the first impedance matching circuit, the first phase adjustment circuit, the second impedance matching circuit, and the second phase adjustment circuit are formed by routing a wiring pattern. Is.

  As a result, discrete components are not included in the transmission circuit and the reception circuit, and the cost can be reduced.

The seventh invention includes a first substrate on which the wiring pattern is formed, and second and third substrates on which a ground pattern is formed, so that the ground pattern overlaps the wiring pattern. The second substrate and the third substrate are provided on the front and back surfaces of the first substrate.

  Accordingly, the transmission circuit and the reception circuit, particularly the first phase adjustment unit included in the transmission circuit can be electromagnetically cut off from the outside, and stable phase adjustment and filtering characteristics can be obtained.

In addition, an eighth invention is the fourth substrate on which the first amplifier and the second amplifier are mounted, and the fourth substrate is provided on the fourth substrate and the second substrate or the third substrate. Via holes for electrically connecting the first substrate are provided, the transmission signals amplified by the first amplifier are supplied to the transmission circuit through the via holes, and the reception signals received by the antenna are 9. The wireless communication apparatus according to claim 8, wherein the wireless communication apparatus is supplied to two amplifiers.

  As a result, components that have a large circuit scale and cannot be configured by routing the wiring pattern can be easily surface-mounted.

The ninth invention has a plurality of via hole groups connecting the second substrate and the third substrate, and the via hole group is sandwiched between the second substrate and the third substrate. The first substrate is provided so as to surround the transmission circuit and the reception circuit.

  Accordingly, the transmission circuit and the reception circuit, particularly the first phase adjustment unit included in the transmission circuit can be electromagnetically cut off from the outside, and stable phase adjustment and filtering characteristics can be obtained.

In the tenth aspect of the invention, the first phase adjustment circuit is composed of two saddle-type low-pass filters of the first and second stages connected in series, of which the termination of the first stage and the second stage of the second stage The capacitor arranged at the start end is shared by one capacitor.

  As a result, the characteristics of the first phase adjustment circuit can be easily adjusted.

According to a first aspect of the invention, the output of the first amplifier is a differential output signal, and the differential output is provided between the first impedance matching circuit and the first phase adjustment circuit in the transmission circuit. Is provided with a first balun for converting the first signal into a single-ended signal, and the first balun includes a parallel circuit for transitioning impedance so that the absolute value of the voltage reflection coefficient Γ is increased when the first amplifier is deactivated. It is what was included.

  As a result, the differential signal output from the first amplifier can be easily converted into a single-ended signal, and the impedance on the real axis of the Smith chart is halved, and the transmission circuit and antenna when the first amplifier is activated Thus, the impedance of the transmission circuit when the first amplifier is inactivated can be made high impedance.

The first and second invention, the input of the second amplifier is the signal of the differential input, in the reception circuit, between the second impedance matching circuit and the second phase adjustment circuit, wherein the single-ended input The second balun includes a parallel circuit that transitions the impedance so that the absolute value of the voltage reflection coefficient Γ is increased when the second amplifier is deactivated. It is a thing.

  As a result, the single-ended signal input to the second amplifier can be easily converted into a differential signal, and the impedance on the real axis of the Smith chart is halved, and the receiving circuit and antenna when the second amplifier is activated The impedance of the receiving circuit when the second amplifier is inactivated can be made high impedance.

The invention of the first 3 is obtained by forming the second balun resonator having a band-pass filter characteristics.

As a result, the second balun can be used not only as a converter between a single-ended signal and a differential signal but also as a band-pass filter.
(First embodiment)

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1A is an overall perspective view of the base unit 100 of the wireless communication apparatus according to the first embodiment, and FIG. 1B is an overall perspective view of the handset 200 of the wireless communication apparatus. Hereinafter, an outline of the parent device 100 and the child device 200 of the wireless communication apparatus according to the first embodiment will be described with reference to FIGS. 1A and 1B.

  In the first embodiment, a digital cordless telephone mainly compliant with DECT (Digital Enhanced Cordless Telecommunications) will be described as an example. DECT is a standard for digital cordless telephones established in 2011. It uses a frequency of 1.9 GHz (1,895,616 Hz to 1,902,528 Hz), and the communication method is TDMA-WB (time division multiple). Connection method). In DECT, communication troubles due to radio wave interference with other devices can be reduced, and 1.9 GHz, which is the frequency band to be used, has no interference with wireless LANs and microwave ovens. . DECT is known as a method capable of communicating wideband voice / data, and the frequency band can be efficiently used by constantly monitoring the usage state of the frequency channel and selecting the optimum channel by the apparatus itself.

  Note that the characteristic configuration of the wireless unit 12 to be described later is not limited to the DECT method, but for example, GSM (registered trademark) (Global System for Mobile Communications) method mobile phones, smartphones, PHS, The present invention can be applied to WLAN, portable information terminals (tablets) having a wireless transmission / reception function in general, and can also be applied to a car phone and a mobile phone adopting a DCS (Digital Cellular System) system.

  In FIG. 1 (a), the user uses the display unit 6 and the operation unit 7 of the main unit 100 to call the telephone number of the other party and input a key as in the case of a normal landline telephone, and a public line (not shown) Voice data is exchanged with other telephones connected to (wired). The base unit 100 is provided with a microphone 8 and a speaker 9 so that the user can talk with the other party in a so-called hands-free state.

  In FIG. 1B, the user can transmit and receive audio data via the parent device 100 using the child device 200. Also in the slave unit 200, the user uses the display unit 14 and the operation unit 15 to key-in the telephone number of the other party to call. The handset 200 is also provided with a microphone 16 that acquires sound to be transmitted, a speaker 17 for calling, and a speaker for ringer 18 that outputs sound obtained by demodulating the received signal.

  Base unit 100 has an antenna (base unit antenna) 5 and transmits / receives digital audio data superimposed on a carrier wave of a predetermined frequency to / from antenna 13 (slave unit antenna) provided in slave unit 200. . Thereby, it is possible to make a wireless communication between the parent device 100 and the child device 200.

  FIG. 2 is a block configuration diagram showing an outline of the base unit 100 of the wireless communication apparatus. In addition to the display unit 6, the operation unit 7, the microphone 8, and the speaker 9 that have already been described, the base unit 100 includes a telephone line interface 1 as an external interface. The base unit 100 is connected via the telephone line interface 1. Connect to the public line. Further, the base unit 100 is provided with a storage unit 3 composed of a flash memory or the like. For example, when the base unit 100 is used as an answering machine, it is transmitted from the other party. The voice data is digitized and stored.

  The base unit 100 is provided with a signal processing unit 10, which is mounted on an analog multiplexer 10a, a codec 10b, a CPU block 10f, an encoding / decoding unit 10d, a TDD / TDMA processor 10e, and a CPU block 10f. The digital speech processor (voice processor) 10c and the amplifier module 30 are configured. Hereinafter, components of the signal processing unit 10 will be described.

  The analog multiplexer 10a has one input / output channel for an audio signal input via the telephone line interface 1, an audio signal received by the microphone 8, and an audio signal output to the speaker 9 (both audio signals are analog signals). Select a channel.

  The codec 10b is a so-called audio codec, and specifically includes a DA converter and an AD converter that mutually convert a digital signal and an analog signal. The analog audio signal input to the base unit 100 via the telephone line interface 1 and the analog audio signal acquired by the microphone 8 are AD converted by the codec 10b to generate a digital audio signal. On the other hand, a digital audio signal that has been digitally processed by a digital speech processor 10c described later is DA-converted by the codec 10b to generate an analog audio signal, and the analog audio signal is output from the speaker 9.

  The CPU block 10f includes a CPU (Central Processing Unit) (not shown), an EEPROM (Electrically Erasable Programmable Read Only Memory) that stores a control program, a RAM (read only memory) as a work memory, a bus that combines these, and the like. The operation of the entire machine 100 is controlled. The CPU block 10f is equipped with a digital speech processor 10c that executes audio signal processing. The digital speech processor 10c cancels noise or echo, or emphasizes a specific voice frequency for a digital voice signal AD-converted by the codec 10b or a digital voice signal decoded by an encoding / decoding unit 10d described later. , Performing encryption / decryption. In general, these audio signal processing is often based on filtering processing by high-speed convolution, and processing may be performed by a DSP (Digital Signal Processor) specialized for these signal processing. The CPU and the digital speech processor 10c (not shown) may be configured by one processor. Further, the entire signal processing unit 10 may be configured by one DSP.

  The encoding / decoding unit 10d encodes a digital signal to be wirelessly communicated (transmitted) via the antenna 5 out of the output of the digital speech processor 10c, while the signal received through the antenna (here, already (Digital). The encoding / decoding unit 10d employs, for example, an ADPCM (Adaptive Differential Pulse Code Modulation) method. In the ADPCM system, the amount of data can be reduced without degrading sound quality by digitizing the difference between the data of interest and the data digitized immediately before. In a simple PCM (Pulse Code Modulation) method, it is said that 16-bit data can be compressed to about 12 bits without degrading sound quality. This improves the data transmission efficiency.

  A TDD / TDMA (Time Division Duplex / Time Division Multiple Access) processor 10e divides a carrier frequency used for transmission into units called time slots and enables a plurality of communications at the same frequency (time division multiple access). Thus, since the same frequency is shared and data is transmitted and received in a very short time, it is possible to make it appear as if transmission and reception are being executed substantially simultaneously. Furthermore, in TDMA, by using together FDMA (Frequency Division Multiple Access) which divides | segments a frequency band, many channels can be ensured and frequency interference can be avoided. As described above, the TDD / TDMA processor 10e periodically switches between transmission and reception within a short time. Specifically, the TDD / TDMA processor 10e is provided in the radio unit 12 (refer to FIG. 4 hereinafter). The power amplifier 31 (first amplifier, hereinafter referred to as PA) that amplifies the transmitted signal and the low noise amplifier 36 (second amplifier, hereinafter referred to as LNA) that amplifies the received signal are turned on (activated) and off (not activated). It functions as a control unit that alternately and exclusively repeats (activation). This activation and deactivation may be realized, for example, by controlling power supply to the PA 31 and the LNA 36, or may be configured such that a gate circuit is provided at any of the input / output stages of each amplifier. Thus, the control is performed so that the LNA 36 is always OFF when the PA 31 is ON, and the PA 31 is always OFF when the LNA 36 is ON. This alternate and exclusive control is periodically performed at, for example, about 200 Hz.

  The TDD / TDMA processor 10e includes a DA converter and an AD converter (not shown). The TDD / TDMA processor 10e converts a digital signal (transmission signal) input from the digital speech processor 10c via the encoding / decoding unit 10d into an analog signal by a DA converter and outputs the analog signal to the amplifier module 30. The analog signal (received signal) input from the LNA 36 of the wireless unit 12 via the amplifier module 30 is converted into a digital signal by an AD converter and output to the encoding / decoding unit 10d. As described above, an analog signal interface including the amplifier module 30 is configured between the TDD / TDMA processor 10 e and the wireless unit 12.

  In the wireless unit 12, the transmission signal (analog signal) output from the amplifier module 30 is emitted from the antenna 5 via the transmission circuit 37 (see FIG. 4), and the reception signal (analog signal) received by the antenna 5 is used. The data is output to the TDD / TDMA processor 10e via the receiving circuit 38 (see FIG. 4). The configurations of the transmission circuit 37 and the reception circuit 38 included in the amplifier module 30 and the wireless unit 12 will be described in detail later.

  FIG. 3 is a block configuration diagram showing an outline of the handset 200 of the wireless communication apparatus. As described above, the slave unit 200 includes the display unit 14, the operation unit 15, the microphone 16, the call speaker 17, the storage unit 11, the ringer speaker 18, the antenna 13, the signal processing unit 10, and the radio unit 12. ing.

  The handset 200 is generally designed to be small in order to have portability, but the basic function is the same as that of the base unit 100 described with reference to FIG. That is, the configuration and function of the signal processing unit 10 and the radio unit 12 of the slave unit 200 are substantially the same as those of the signal processing unit 10 and the radio unit 12 described in the base unit 100 (therefore, the same reference numerals are assigned). ) Therefore, detailed description of the slave unit 200 will be omitted. However, when the actual board configuration and the like are described below, the description will be continued with reference mainly to the slave unit 200 configured to be smaller for convenience.

  FIG. 4 is a block configuration diagram illustrating an outline of the amplifier module 30 and the wireless unit 12 provided in the signal processing unit 10. The wireless unit 12 includes a transmission circuit 37 and a reception circuit 38. The transmission circuit 37 and the reception circuit 38 are electrically connected at a connection point 39, and the connection point 39 is connected to the antenna 13. Here, “electrically connected” does not mean that “no element is interposed between the output terminal of the transmission circuit 37 and the input terminal of the reception circuit 38”. As described later, the case where the output of the transmission circuit 37 and the input of the reception circuit 38 are connected via a capacitor is also included in “electrically connected”. This is because when the use band is a high frequency as in DECT, the capacitors provided at the two end points described above have a DC cut function, but can conduct a high frequency signal.

  The amplifier module 30 includes a PA (first amplifier) 31 and an LNA (second amplifier) 36. The PA 31 is a power amplifier, and the input terminal Tx of the PA 31 is connected to the TDD / TDMA processor 10e of the signal processing unit 10, and the transmission signal (analog signal) output from the TDD / TDMA processor 10e is input. The LNA 36 is a low noise amplifier, and the received signal (analog signal) output from the receiving circuit 38 is input and amplified. The output end Rx of the LNA 36 is connected to the TDD / TDMA processor 10e, and the amplified received signal (analog signal) is passed to the TDD / TDMA processor 10e. The amplifier module 30 is mainly configured by an analog circuit, and the signal unit 10 is configured as a so-called digital / analog mixed chip.

  The TDD / TDMA processor 10e outputs a control signal (not shown) to the amplifier module 30 and controls activation (ON) and deactivation (OFF) of the PA 31 and the LNA 36. This inactive state includes not only the power supply of the entire PA 31 but also a part of the power supply, the PA 31 internal circuit, the input / output signal by the gate circuit, and the like.

  The transmission circuit 37 includes a first impedance matching circuit 32 and a first phase adjustment circuit 33. The first impedance matching circuit 32 matches the impedance between the output of the transmission circuit 37 and the antenna 13 when the PA 31 is activated, while the impedance of the transmission circuit 37 and the antenna 13 when the PA 31 is deactivated. Make it inconsistent.

  The first phase adjustment circuit 33 rotates the impedance uniformly on the connection point 39 side of the transmission circuit 37 regardless of whether the PA 31 is active or inactive. When the PA 31 is activated, the impedance matching state When the LNA 36 is inactivated, the high impedance state is changed.

  The reception circuit 38 includes a second impedance matching circuit 35 and a second phase adjustment circuit 34. The functions of the second impedance matching circuit 35 and the second phase adjustment circuit 34 are basically the same as those of the transmission circuit 37 described above. That is, the second impedance matching circuit 35 matches the impedance between the antenna 13 and the receiving circuit 38 when the LNA 36 is activated, while the impedance between the antenna 13 and the receiving circuit when the LNA 36 is deactivated. Is inconsistent.

  The second phase adjustment circuit 34 rotates the impedance uniformly on the connection point 39 side of the reception circuit 38 regardless of whether the LNA 36 is active or inactive. When the LNA 36 is activated, the impedance matching state When the LNA 36 is inactivated, the high impedance state is changed.

  That is, on a horizontal line obtained by dividing a circle on the Smith chart, which is a complex plane, in half up and down (this line represents a pure resistance component, hereinafter referred to as a real axis), 50 Ω point (normalized impedance is 1 Ω) When the PA31 is activated, the first impedance matching circuit 32 changes the impedance of the output of the transmission circuit 37 to the vicinity of the R50 point when the PA31 is activated. In a state where is inactivated, the output impedance of the transmission circuit 37 is shifted to a position far away from the R50 point.

  Then, the first phase adjustment circuit 33 rotates the impedance on a circle around the R50 point at the output of the transmission circuit 37 (that is, the connection point 39). Specifically, the first phase adjustment circuit 33 rotates the locus of impedance by causing a phase shift in the transmission signal. Here, since the first phase adjustment circuit 33 rotates the impedance uniformly on a circle centering on the R50 point regardless of whether the PA 31 is activated or deactivated, the impedance when the PA 31 is activated Keeps its alignment even with rotation (because it is near the R50 point). The impedance when one PA 31 is deactivated changes greatly by rotation, and can be shifted to a high impedance state by adjusting the rotation angle (that is, the phase shift amount of the transmission signal).

  The first impedance matching circuit 32 and the first phase adjustment circuit 33 in the transmission circuit 37 and the second impedance matching circuit 35 and the second phase adjustment circuit 34 in the reception circuit 38 are characteristic components in the first embodiment. These functions will be described in detail later using a Smith chart.

  FIG. 5 is a configuration diagram showing a specific configuration of the transmission circuit 37 and the reception circuit 38, and FIG. 6 is an explanatory diagram showing a state where the transmission circuit 37 and the reception circuit 38 are mounted on the substrate. FIG. 8 is an explanatory diagram showing actual dimensions (dimensions) on the substrate of the transmission circuit 37 and the reception circuit 38, and FIG. 8 is an explanatory diagram showing a state in which the signal processing unit 10 and its peripheral circuits are mounted on the substrate. FIGS. 9A to 9D are explanatory diagrams of a configuration for shielding the transmission circuit 37 and the reception circuit 38, and FIG. 9E is an explanatory diagram illustrating a configuration of a multilayer substrate.

  In FIG. 5, the hatched portion from the upper right to the lower left represents a transmission line or inductor, and the hatched portion from the upper left to the lower right represents a capacitor, but the thin lines in the transmission circuit 37 and the reception circuit 38 are dummy lines, It shows only the connection relationship of the components, and has no length or width. Thus, the transmission circuit 37 and the reception circuit 38 include at least an inductor and a capacitor as circuit elements.

  Further, “W” shown in FIG. 7 indicates the width of the wiring pattern constituting the circuit, and “L” similarly indicates the length of the wiring pattern. The numerical value following “W” “L” is an actual numerical value on the substrate, and the unit is [mm].

  In the following description, the substrate on which the transmission circuit 37 and the reception circuit 38 are mounted is referred to as a first substrate 59a, and the substrate on which the signal processing unit 10 is mounted is referred to as a fourth substrate 59d.

  The various capacitors in the following description include a wiring pattern (copper foil) formed on the first substrate 59, and a ground pattern of the second substrate 59b and the third substrate 59c that form a multilayer substrate together with the first substrate 59a. (See FIG. 9E). That is, the glass epoxy resin which is the main material of the substrate constitutes the insulating layer in the capacitor. One end of these capacitors is connected in parallel to the circuit, and the other end is the ground pattern itself and is grounded. The capacitance of the capacitor can be adjusted by the distance between patterns on the first substrate 59a, the second substrate 59b, and the third substrate 59c (that is, the thickness of the substrate).

  FIG. 8 shows the layout of the wiring pattern of the fourth substrate 59d. The signal processing unit 10 mounted on the fourth substrate 59d is a rectangular line whose outer frame portion is a dotted line, and the DC cut capacitor 46 is blacked out. It is described as.

  Hereinafter, the configurations of the transmission circuit 37 and the reception circuit 38 of the first embodiment and their peripheral configurations will be described in detail with reference to FIGS. 5, 6, 7, 8, and 9.

  As shown in FIG. 6, the first impedance matching circuit 32 (excluding some transmission lines) constituting the transmission circuit 37, the first phase adjustment circuit 33, the first balun 40, and the second constituting the reception circuit 38. The impedance matching circuit 35 (except for some transmission lines), the second phase adjustment circuit 34, and the second balun 41 are formed on the first substrate 59a only by the wiring pattern.

  Further, as shown in FIG. 8, the transmission lines constituting part of the first impedance matching circuit 32 and the second impedance matching circuit 35 are formed on the fourth substrate 59d only by the wiring pattern (details will be described later). To do).

  Thus, the cost can be significantly reduced by not using any discrete parts. In FIG. 6, the hatched portion indicated by GP represents a ground pattern. Thus, the transmission circuit 37 and the reception circuit 38 are surrounded by the ground pattern GP even in the substrate.

  Further, as shown in FIG. 9E, the first substrate 59a is one of the multilayer substrates. In the first embodiment, a four-layer multilayer substrate is used, and a fourth substrate 59d, a second substrate 59b, a first substrate 59a, and a third substrate 59c are laminated in this order from the upper layer to the lower layer, and the total thickness is about 1 mm. It is said that. Among these, the signal processing unit 10 incorporating the amplifier module 30 (not shown) is mounted on the uppermost fourth substrate 59d.

  As shown in FIGS. 9B and 9D, in the second substrate 59b and the third substrate 59c as well as the first substrate 59a, GP shows a ground pattern, and the second substrate 59b and the third substrate 59c are almost the same. A ground pattern is formed on the entire surface. The above-described transmission circuit 37, reception circuit 38, power supply line 45, and the like are formed on the first substrate 59a.

  9A to 9D, PA indicates a transmission / reception circuit arrangement region on the first substrate 59a, and corresponding regions on the second substrate 59b, the third substrate 59c, and the fourth substrate 59d. The first substrate 59a has a configuration in which the main surface is sandwiched between the second substrate 59b and the third substrate 59c. In the second substrate 59b and the third substrate 59c, a ground pattern is formed except for a part of the region corresponding to the transmission / reception circuit arrangement region PA of the first substrate 59a, thereby forming on the first substrate 59a. The transmission circuit 37 and the reception circuit 38 are shielded from external electromagnetic waves by an electromagnetic shield.

  Further, as shown in FIG. 6, in the first substrate 59 a, the second impedance matching that constitutes the first impedance matching circuit 32, the first phase adjustment circuit 33, the first balun 40, and the receiving circuit 38 that constitute the transmission circuit 37. A number of via holes 55 are provided around the circuit 35, the second phase adjustment circuit 34, and the second balun 41. The via hole 55 interconnects the ground patterns of the second substrate 59b and the third substrate 59c sandwiching the first substrate 59a, and the transmitting circuit 37 and the receiving circuit 38 are connected to the first substrate 59a on which the first substrate 59a is formed. These are protected by electromagnetic shields not only on both principal surface sides but also in the substrate.

  However, the electromagnetic shield constituted by the second substrate 59b and the third substrate 59c is partially provided with a window area BA (see FIGS. 9B and 9D), and the window area BA is grounded. The pattern is not formed. In a region corresponding to the window region BA in the first substrate 59a, a resonator of a second balun 41 (see FIG. 5 and the like) described later is provided, and an adverse effect caused by a capacitance component generated by sandwiching this portion with a ground pattern. (Deterioration of wavelength selection performance of the resonator) is prevented.

  Hereinafter, the individual elements constituting the transmission circuit 37 will be described in the order of the path through which the transmission signal passes.

  As shown in FIG. 5, the PA 31 includes a three-stage amplifier. The two stages closer to the input terminal Tx are supplied with power adjusted by the power supply line 45 by the regulator 29, and are mainly used as operating power for the logic circuit. A configuration for supplying power to the third-stage amplifier (final stage amplifier 31a) closest to the input side of the transmission circuit 37 will be described later.

  Here, as already described, in the signal processing unit 10 (which includes the amplifier module 30) mounted on the fourth substrate 59d which is the uppermost substrate (see FIGS. 8 and 9E), The PA 31 outputs a differential signal, and this differential signal is transmitted from the uppermost fourth substrate 59d to the third first substrate 59a via the via holes 43a and 43b.

  The first impedance matching circuit 32 includes a pair of transmission lines LI1 and LI2 and capacitors C1 and C2 that respectively handle two differential signals. The transmission lines LI1 and LI2 are formed by drawing a wiring pattern on the fourth substrate 59d (see FIG. 8), and are connected in series to the differential signal output terminal of the PA 31. The capacitors C1 and C2 are formed by routing a wiring pattern on the first substrate 59a (see FIG. 6), one end of which is connected in parallel to the output side of the transmission lines LI1 and LI2, and the other end is grounded.

  Here, the lengths of the transmission lines LI1 and LI2 and the capacitances of the capacitors C1 and C2 (the frequency of the signal applied to these elements and the length and width (area) of the wiring pattern on the substrate on which they are formed) Is determined so as to achieve impedance matching between the transmission circuit 37 and the antenna 13 with the PA 31 activated. Specifically, the impedance when the PA 31 is activated is adjusted by setting the capacitance to, for example, 3.6 pF according to the shape (area) of the capacitors C1 and C2 shown in FIG. The impedance adjustment process of the transmission circuit 37 by the inductors LI1 and LI2 and the capacitors C1 and C2 constituting the first impedance matching circuit 32 will be described in detail later using a Smith chart.

  The output of the first impedance matching circuit 32 is passed to the first balun 40. The first balun 40 converts a differential signal into a single-ended signal, and includes an inductor L3. As shown in FIG. 7, the specific length of the wiring pattern constituting the inductor L3 is 38 mm.

Now, in the 1.9 GHz band used in DECT, the spatial wavelength λ is
λ = c / f = 3 × 10 ⁸ /1.9×10 ⁻⁹ = 158 mm (where c is the speed of light) (Expression 1)
Is calculated. However, since the first substrate 59a is a single substrate constituting a multilayer substrate and is surrounded by another substrate (dielectric) as an intermediate layer, the wavelength is shortened. In the first embodiment, as the first substrate 59a to the fourth substrate 59d, so-called glass epoxy substrates are used in which a glass fiber cloth is impregnated with an epoxy resin and subjected to thermosetting treatment to form a plate. Since the rate ε = 4.2, the in-substrate wavelength λg is
λg = λ / √ε = 158 mm / 4.2 = 77 mm (Expression 2)
It becomes. A transmission line length (77 / 4≈19 mm in the above example) that becomes λg / 4 is a basic unit in designing a wiring pattern.

  According to FIG. 7, the length of L3 constituting the first balun 40 is 38 mm, which corresponds to approximately λg / 2. When a transmission line is added to a certain impedance load and the signal phase is changed, the coordinates indicating the impedance change on the Smith chart so as to rotate on a circle centered on the R50 point. That is, the impedance can be changed by changing the signal phase. For example, assuming that the initial impedance Z = 0, every time the transmission line length changes by λg / 4, the impedance Z changes to repeat ∞ and 0 (both are points on the real axis). In the case of the first balun 40, the signal phase does not change between the balun inputs and outputs by forming the inductor L3 with a length of λg / 2. However, since the first balun 40 has a configuration for converting a differential signal into a single-ended signal, the transmission circuit 37 viewed from the antenna 13 side includes a parallel circuit. Therefore, when the output impedance of the first impedance matching circuit 32 is only the component on the real axis of the Smith chart (R0), the impedance of the transmission circuit 37 viewed from the antenna 13 is R0 / 2 due to the first balun 40 being interposed. Halved. As a result, the output impedance of the first balun 40 is set in the vicinity of the R50 point on the Smith chart, and the impedance of the output of the first balun 40 is matched with the antenna 13 when the PA 31 is activated.

  FIG. 10A is a configuration diagram showing the configuration of the first phase adjustment circuit 33, and FIG. 10B is an explanatory diagram of an equivalent circuit of the first phase adjustment circuit 33. Hereinafter, the configuration and operation of the first phase adjustment circuit 33 will be described with reference to FIGS.

  As shown in FIG. 10A, the first phase adjustment circuit 33 arranges inductors L4 and L5 in series from the input stage side, between the input terminal and the inductor L4, between the inductors L4 and L5, and between the inductor L5 and One end of capacitors C3, C4, and C5 is connected between the output ends, and the other end is grounded. Thus, the first phase adjustment circuit includes at least an inductor and a capacitor as explicit circuit elements. As shown in the equivalent circuit of FIG. 10 (b), this configuration is obtained by arranging two bowl-shaped low-pass filters in series, and the capacitor C4 between the two inductors L4 and L5 has a low-pass filter. The first stage and the second stage are shared. Since the low-pass filter has an effect of delaying the signal phase, the impedance can be rotated around the R50 point on the Smith chart also by this configuration. However, if the attenuation characteristic of the low-pass filter is to be improved, the signal phase will be greatly shifted (delayed) as a result, and the rotation on the Smith chart at this time will exceed one round.

  The capacitor C4 disposed between the inductors L4 and L5 is a low-pass filter using substantially any capacitance value as long as the capacitances of the output side of the first stage and the input side of the second stage are the same. A filter can be configured. By adjusting the value of the capacitor C4, it is possible to easily set the attenuation amount and phase adjustment of the entire low-pass filter with a high degree of freedom. For example, if the attenuation characteristic is steep, the value of C4 may be increased.

  When a low-pass filter is configured with a conventional discrete element, a parasitic inductance component and a parasitic capacitance component are generated by the element itself, and the attenuation characteristic in the high frequency region is particularly insufficient, so that phase adjustment is practically difficult. In the first embodiment, a wiring pattern is routed to form a low-pass filter as a phase adjustment unit, and a high-frequency characteristic that is practically sufficient is obtained for the first time by forming a low-pass filter using a multilayer substrate as described above. Yes.

As shown in FIG. 7, the capacitor C3 provided at the input end of the first phase adjustment circuit 33 has W = 2.2 mm and L = 5.0 mm (area = 11 mm ² ). A capacitor C5 provided at one output end has W = 2.9 mm and L = 3.8 mm (area = 11.02 mm ² ), and the capacities of the capacitors C3 and C5 are slightly different. In this way, by generally changing the capacitance values of the capacitors at the first stage input terminal and the second stage output terminal by a minute amount, the band of the low-pass filter can generally be expanded.

  As described above, when PA 31 is activated in the transmission circuit 37, the output impedance of the first balun 40 is already matched with the antenna 13 (that is, the impedance near the R50 point on the Smith chart). Value). When the signal phase is changed in a state where such matching is achieved, the impedance transitions on a circle centered on the R50 point. In other words, when the impedance is originally matched, the impedance is in the vicinity of the R50 point that is the center of rotation, so that the established matching does not fail even if the signal phase is changed.

  Theoretically, the signal phase can be changed by adjusting the length of the transmission line connected in series with the impedance load. However, in the first embodiment, the first phase adjustment circuit 33 is configured by a low-pass filter. Yes. Here, the reason why the phase is not changed depending on the length of the transmission line is that the line length may become extremely long by routing the transmission line. In general, when the attenuation characteristic is improved in a low-pass filter, the phase delay is increased. However, if this is to be realized only by the transmission line length, for example, 19 mm × 3 = 54 mm is required to achieve a phase delay of 3 / 4λg. Wiring length is required. The magnitude of the influence of the line length of 54 mm on the circuit design can be easily estimated by looking at the dimensions in FIG. 7, but a low-pass filter can be easily realized with a two-stage configuration.

  In general, the impedance of the output terminal of the PA 31 differs between when the PA 31 is activated and when it is deactivated, and the first impedance matching circuit 32, the first balun 40, and the first phase adjustment circuit 33 described above. Impedance matching is achieved only when PA 31 is activated. In other words, when PA 31 is inactive, the output impedance of the first balun 40 is not at the R50 point on the Smith chart (that is, impedance matching with the antenna 13 is not achieved). Therefore, if the impedance characteristic is shifted to the state separated from the R50 point by the first impedance matching circuit 32 and the first balun 40 and the signal phase of the transmission signal is changed by the first phase adjustment circuit 33, the PA 31 is not effective. The impedance of the transmitting circuit 37 when activated is greatly rotated (changed) around the R50 point, and can be shifted to a high impedance state according to the amount of change in the signal phase.

  As a result, in a state where PA 31 is activated (that is, at the time of transmission), impedance matching is achieved when the output terminal of the transmission circuit 37 is viewed from the antenna 13, while PA 31 is deactivated (that is, when the PA 31 is inactive). At the time of reception), the output terminal of the transmission circuit 37 is in a high impedance state when viewed from the antenna 13, and the reception signal is prevented from flowing into the transmission circuit 37 side.

  In the first embodiment, as described above, the first phase adjustment circuit 33 constitutes a low-pass filter, but may have a band-pass filter characteristic.

  The transmission signal subjected to the signal processing described above passes through the first connection point 39a and then is sent from the first substrate 59a to the uppermost fourth substrate 59d via the via hole 43e. And it is emitted in the air from the antenna 13 connected via the DC cut capacitor 46 on the fourth substrate 59d. The voltage applied to the power supply line 45 by the DC cut capacitor 46 does not leak to the antenna 13 side, and only the transmission signal is sent to the antenna.

  Hereinafter, returning to FIGS. 5, 6, 7, 8, and 9, the individual elements constituting the reception circuit 38 will be described in the order of the path through which the reception signal passes.

  The reception signal received by the antenna 13 passes through the second connection point 39b and is then sent from the fourth substrate 59d to the reception circuit 38 of the first substrate 59a through the via hole 43f. The received signal is first input to the second phase adjustment circuit 34.

  As shown in FIGS. 5 and 6, the second phase adjustment circuit 34 includes only the transmission line LI3. In the transmission circuit 37 described above, the phase adjustment circuit is configured by a low-pass filter because it is necessary not only to shift the signal phase but also to remove the signal noise. However, in the reception circuit 38, the LNA 36 is less likely to be a noise source. Is not required, and the impedance of the receiving circuit 38 in a state where the LNA 36 is inactive can be changed to a high impedance state by simply connecting a transmission line in series with the impedance load. Of course, this is a configuration adapted to the characteristics of the LNA 36 employed in the first embodiment, and depending on the other LNA 36, the line length may be longer, but in any case, the wiring pattern length is adjusted. Matching can be easily achieved. Of course, a filter that positively rotates the signal phase, such as the first phase adjustment circuit 33 of the transmission circuit 37, may be provided.

  The output of the second phase adjustment circuit 34 is input to the second balun 41. The second balun 41 is connected in parallel to the input end thereof, and is connected in parallel to the capacitor C11 having the other end grounded, inductors L12 and L13 provided on the substrate and facing each other, and both ends of the inductor L13. And capacitors C12 and C13 having the other end grounded. In FIG. 6, the capacitors C12 and C13 are shared with the capacitors C14 and C15 constituting the second impedance matching circuit 35.

  In the second balun 41, a received signal which is a single-ended signal is converted into a differential signal (differential input). Unlike the first balun 40 included in the transmission circuit 37, a transformer, That is, a resonator is configured. Since only an electromagnetic wave having a frequency satisfying the resonance condition can exist inside the resonator, the second balun 41 has a practical bandpass filter characteristic. As a result, an electromagnetic wave having an unnecessary frequency is eliminated from the signal received by the antenna 13. The second balun 41 is configured to convert a single-ended signal into a differential signal, so that when the second balun 41 is viewed from the antenna, the input impedance of the LNA 36 is Smith by the second impedance matching circuit 35 described later. On the premise that the transition is made to the real axis on the chart, it becomes 1/2 of the input impedance of the second impedance matching circuit 35. As described above, the second balun 41 is not provided with a ground pattern at the facing position (see the window area BA in FIGS. 9B and 9C), thereby improving the characteristics of the bandpass filter. ing.

  The output of the second balun 41 is input to the second impedance matching circuit 35. The second impedance matching circuit 35 is composed of a pair of capacitors C14 and C15 and transmission lines LI5 and LI6 that respectively handle two differential signals. The capacitors C14 and C15 are formed by routing a wiring pattern on the first substrate 59a (see FIG. 6), one end of which is connected in parallel to the input side of the transmission lines LI5 and LI6, and the other end is grounded. The transmission lines LI5 and LI6 are formed by routing a wiring pattern on the fourth substrate 59d (see FIG. 8), and are connected in series to the differential signal input terminal of the LNA 36.

  Here, the lengths of the transmission lines LI5 and LI6 and the capacitances of the capacitors C14 and C15 (the frequency of the signal applied to these elements and the length and width (area) of the wiring pattern on the substrate on which they are formed) Is determined so as to achieve impedance matching between the receiving circuit 38 and the antenna 13 with the LNA 36 activated. Specifically, for example, by setting the capacitance according to the shape (area) of the capacitors C14 (but including the capacitance of C12) and C15 (including the capacitance of C13) shown in FIG. The impedance when the is activated is adjusted.

  The output of the second impedance matching circuit 35 is sent from the first substrate 59a to the uppermost fourth substrate 59d via the via holes 43c and 43d, and is included in the signal processing unit 10 mounted on the fourth substrate 59d. It is input to 30 LNAs 36. The LNA 36 amplifies the received signal and sends it to the TDD / TDMA processor 10e.

  Hereinafter, the configuration (configuration for supplying power) of the power supply line 45 of the first embodiment will be described with reference to FIGS. 5, 7, and 8.

  As shown in FIG. 5, the power supply line (power supply) 45 includes a capacitor C21 and an inductor L21, and one end of the inductor L21 is connected to the output end of the transmission circuit 37 at a first connection point 39a. As shown in FIG. 7, the capacitor C21 connected to the power supply line 45 forms an open stub 56 on the circuit. Here, a stub is a distributed constant line that is connected in parallel to a transmission line in a high-frequency circuit. In particular, a stub with an open end depending on the type of termination load is called an open stub. The In the first embodiment, the length of the open stub 56 is set to 19 mm. When the connection point between the open stub 56 and the inductor L21 is P1, the transmission line length of the inductor L21 disposed between the first connection point 39a and the point P1 (that is, inserted in series with the power supply line 45). Is also 19 mm. This 19 mm corresponds to λg / 4 as described above. Therefore, with this configuration, when the impedance of the power supply line 45 is 0, the impedance of the terminal end of the open stub 56 and the output terminal of the transmission circuit 37 (that is, the first connection point 39a) viewed from the power supply line 45 is Means ∞. Here, since the circuit behaves as impedance = ∞ only for the carrier wave of 1.9 MHz, the output of the transmission circuit 37 modulated to 1.9 MHz cannot flow into the power supply line 45. Similarly, a 1.9 MHz reception signal received by the antenna 13 cannot flow into the power supply line 45. Therefore, with this configuration, it is possible to reliably prevent noise from entering the power supply from the transmission circuit 37 and the antenna 13.

  On the other hand, DC power is supplied from the power supply line 45 to the final stage amplifier 31a of the PA 31 via the first connection point 39a and the transmission circuit 37. The transmission power (aerial power) in the DECT standard is about 10 mW on average, but this final stage amplifier 31a consumes relatively large power and is activated (ON) and deactivated (OFF) at several hundred Hz. Since it repeats, it tends to be a noise source due to rush current. In the conventional configuration, the power line 45 is directly connected to the amplifier module 30 to supply power, and noise generated in the final stage amplifier 31a is transmitted to various electrical elements constituting the wireless communication device via the power line. There is a possibility of propagation, and noise countermeasures for the final stage amplifier 31a have been an issue. That is, if power is directly supplied to the final stage amplifier 31a, a power supply circuit that cuts off all the harmonic components (2 × f0, 3 × f0...) Of the fundamental wave f0 becomes necessary, which complicates.

  However, according to the first embodiment, even if noise is generated in the final stage amplifier 31a, this noise passes through the transmission circuit 37, and the first phase adjustment circuit 33 (inductor provided in the transmission circuit 37). And a circuit low-pass filter including a capacitor). That is, in the case of DECT, only the fundamental wave f0 of 1.9 GHz needs to be cut off. Furthermore, even if other noise components are mixed in via the power supply line 45, the noise components can be attenuated by this low-pass filter. That is, it is possible to suppress both noise on the transmission signal and noise from the power source side by a single low-pass filter formed by the circuit elements.

  Further, since the power supply line 45 connected at the first connection point 39a is blocked by the open stub 56 having the transmission line corresponding to the length of λg / 4 already described and the inductor L21, noise caused by the carrier wave is not generated. The power line 45 is not mixed. This prevents noise generated in the final stage amplifier 31a from propagating through the power supply line 45 to the entire apparatus.

  On the other hand, since the LNA 36 to which the output of the receiving circuit 38 is connected generally has low power consumption and does not generate high frequency noise, it is directly supplied with power from the power line 45 (via the signal processing unit 10) ( Not shown).

  Now, according to FIG. 5, the configuration of the first embodiment includes a first connection point 39 a that connects the output of the transmission circuit 37 and the power supply line 45, and a second connection point that connects the input of the antenna 13 and the reception circuit 38. 39b, and the first connection point 39a and the second connection point 39b are connected via a capacitor (DC cut capacitor 46).

  More specifically, the connection between the power supply line 45 and the output end of the transmission circuit 37 is performed at the first connection point 39a of the first substrate 59a (see FIG. 6). The first connection point 39a is guided to the fourth substrate 59d through the via hole 43e (see FIG. 8). On the other hand, the input end of the receiving circuit 38 is led from the first substrate 59a to the fourth substrate 59d through the via hole 43f, and is connected to the antenna 13 on the fourth substrate 59d to form the second connection point 39b (FIG. 8). The first connection point 39a and the second connection point 39b are connected to each other through a capacitor 46 that is surface-mounted on the fourth substrate 59d (see FIG. 8).

  Thus, the first connection point 39a and the second connection point 39b are not directly connected. However, as described above, in the high frequency band, for example, 1.9 GHz, which is handled by the wireless communication apparatus of the present invention, the capacitor is practically in a conductive state, and therefore the first connection point 39a and the second connection point 39b are electrically connected. It may be considered that a single connection point 39 connected to the above is constituted. Considering this, the wireless communication apparatus according to the first embodiment includes an antenna 13 that transmits radio waves, and a PA 31 that amplifies a transmission signal transmitted from the antenna 13 (more specifically, a final stage amplifier 31a included in the PA 31). ), A transmission circuit 37 that processes the transmission signal amplified by the PA 31, a power supply line 45 that supplies power to the PA 31, and a connection point 39 that electrically connects the output of the transmission circuit 37 and the antenna 13. It can be said that the power supply line 45 is connected to the connection point 39 and power is supplied to the PA 31 via the transmission circuit 37.

  However, the above description specifies only the peripheral configuration of the transmission circuit 37 of the wireless communication apparatus. When a configuration related to reception is added to the above, the first embodiment includes an antenna 13 for transmitting and receiving radio waves, and an antenna 13. PA31 (more specifically, the final stage amplifier 31a included in PA31) that amplifies the transmission signal transmitted from the transmission circuit 37, the transmission circuit 37 that processes the transmission signal amplified by PA31, and the reception signal received by the antenna 13 A reception circuit 38 for signal processing, a power supply line 45 for supplying power to the PA 31, a connection point 39 for connecting the output of the transmission circuit 37, the input of the reception circuit 38, and the antenna 13, and the power supply line 45 at the connection point 39. It can be said that the power is supplied to the PA 31 via the transmission circuit 37.

  FIGS. 11A to 11D are explanatory views showing the locus of impedance on the Smith chart when the parameters of the elements constituting the high-frequency circuit are changed.

  FIG. 11A shows the locus of impedance on the Smith chart when an inductance is added in series to a 50Ω load. At this time, the impedance transitions so as to rotate on a circle that is in contact with a point of impedance = ∞ on the real axis of the Smith chart (real axis ∞Ω point, hereinafter referred to as “R∞ point”).

  FIG. 11 (b) shows the locus of impedance on the Smith chart when a capacitor is added in parallel with a load of 50Ω (one end is grounded). At this time, the impedance changes so as to rotate on a circle that is in contact with a point of impedance = 0 on the real axis of the Smith chart (actual axis 0Ω point, hereinafter referred to as “R0 point”).

  FIG. 11C shows an impedance locus on the Smith chart when a resistance component (R) is added in parallel to a certain impedance load. At this time, the impedance transitions asymptotically to the R0 point of the Smith chart. If the initial impedance exists on the real axis, the impedance transitions on the real axis in the direction of the point R0.

  FIG. 11D shows an impedance locus on the Smith chart when a transmission line is connected in series to a certain impedance load. At this time, the impedance changes so as to rotate on a circle centered on the R50 point. The rotation of the trajectory on the Smith chart occurs when the signal phase in the transmission line changes. Assuming that the wavelength of the signal is λ, the impedance rotates halfway on the Smith chart every time the signal phase is shifted by ¼λ. That is, in the process of shifting the signal phase by λ, the impedance rotates twice on the Smith chart. Normally, when a signal phase is to be shifted in a high-frequency circuit, a transmission line is added in series to the circuit. For example, a low-pass filter is inserted in series to shift (delay) the signal phase, The same effect can be obtained.

  FIG. 12 is a block diagram schematically showing the transmission circuit 37, and FIG. 13 is an explanatory diagram showing the measured impedance at the output of the PA 31 when the PA 31 is activated (ON) and deactivated (OFF). FIG. 14 is an explanatory diagram for explaining impedance changes caused by the transmission lines LI1 and LI2 when the PA 31 is activated (ON) and deactivated (OFF), and FIG. 15 is an example in which the PA 31 is activated (ON). FIG. 16 is an explanatory diagram showing a change in impedance of the output of the first impedance matching circuit 32 when it is inactivated (OFF). FIG. 16 shows that PA 31 is activated (ON) and deactivated (OFF). FIG. 17 is a diagram illustrating the change in impedance of the output of the first balun 40, and FIG. 17 illustrates the first phase adjustment circuit when the PA 31 is activated (ON) and deactivated (OFF). 33 is an explanatory diagram showing impedance changes of the output of.

  Hereinafter, the state of impedance in each part of the transmission circuit 37 of the first embodiment will be described in detail with reference to FIGS. In the following description, the transmission circuit 37 is taken as an example for simplicity, but the same applies to the reception circuit 38.

  In the following description, the impedance of the transmission circuit 37 viewed from the antenna 13 when the PA 31 is activated is ZonT, and the impedance of the transmission circuit 37 viewed from the antenna 13 when the PA 31 is deactivated is ZoffT. Call it.

  FIG. 13 illustrates the impedance when PA 31 is activated and when PA 31 is deactivated in the output of PA 31 (CX1 in FIG. 12). Circles hatched with dots inside indicate a state in which PA 31 is activated, and circles hatched with diagonal lines indicate a state in which PA 31 is inactivated. In FIG. 13, these two circles are almost equidistant from the R50 point, and the voltage reflection coefficient Γ, which increases from the R50 point toward the outer periphery of the Smith chart, is substantially the same. As will be described below, the wireless communication apparatus according to the first embodiment matches the impedance at the time of activation even when the initial voltage reflection coefficient Γ is substantially the same when activated and deactivated. It has a feature that is not found in the prior art in that the impedance at the time of inactivation is changed to a high impedance state.

  FIG. 14 shows an impedance change caused by the transmission lines LI1 and LI2 (CX2 in FIG. 12) in the first impedance matching circuit 32. By adding the transmission lines LI1 and LI2 in series to the circuit, the signal phase in the line is shifted, and the impedance rotates on a circle centered on the R50 point as described in FIG. 11 (d).

  14 to 17, the solid line circles hatched with dots indicate the impedance when PA31 is ON (after transition), and the broken line circles hatched with dots are the impedance when PA31 is ON (before transition). The solid circles hatched with diagonal lines represent the impedance when the PA 31 is OFF (after transition), and the dashed circles hatched with diagonal lines represent the impedance when the PA 31 is OFF (before transition).

  As shown in FIG. 14, the impedance is rotated on the Smith chart by the transmission lines LI1 and LI2, and the two impedance states are adjusted so that the distances from the point R0 are not uniform. However, even after the impedance is changed by the transmission lines LI1 and LI2 (after the transition), the two solid circles are almost equidistant from the R50 point, and the voltage reflection coefficient Γ is not changed.

  FIG. 15 shows the impedance at the output of the first impedance matching circuit 32 (CX3 in FIG. 12). That is, FIG. 15 shows before and after the impedance change by the capacitors C1 and C2. As described with reference to FIG. 11B, the impedance rotates on a circle in contact with the R0 point on the Smith chart due to the presence of the capacitor. The capacitance value of this capacitor is at least that of the transmission circuit 37 when the PA 31 is ON. The value at which the impedance transitions on the real axis is selected.

  In FIG. 15, the impedance when PA 31 is OFF also changes on the real axis. Although this is not an indispensable condition, it is an ideal transition state, and in order to realize this, “transmission after transition both when the PA 31 is ON and OFF as a result of rotation by the capacitors C1 and C2. It is desirable to set the rotation amount around the R50 point, that is, to set the transmission line lengths of the transmission lines L1 and L2R so that the impedance of the circuit 37 moves on the real axis.

  As described above, the first impedance matching circuit 32 causes ZonT and ZoffT to transition so as to approach the real axis of the Smith chart.

  FIG. 16 shows the impedance at the output of the first balun 40 (CX4 in FIG. 12). As described above, when viewed from the antenna 13, the first balun 40 includes a parallel circuit. Therefore, when the impedance is a pure resistance (that is, on the real axis), the first balun 40 is viewed from the antenna 13. The impedance is halved. As a result, the impedance when PA31 is ON approaches the R50 point, and the impedance when PA31 is OFF approaches the R0 point. That is, the first impedance matching circuit 32 and the first balun 40 work together to bring the impedance when the PA 31 is ON closer to the R50 point, that is, to match the impedance with the antenna 13, and the PA 31 is OFF. Function so that the current impedance is further away from the R50 point (closer to the R0 point).

  Here, the first balun 40 is formally an element that converts a differential signal into a single-ended signal, but as described above, its function includes an impedance matching function. The balun 40 is included in the first impedance matching circuit 32. As described above, the first impedance matching circuit 32 including the first balun 40 is configured so that the voltage reflection coefficient Γ of the transmission circuit 37 when the PA 31 is activated is close to 0 and the PA 31 is deactivated. The impedance is changed so that the voltage reflection coefficient Γ of the transmission circuit 37 becomes large (more precisely, the absolute value of the voltage reflection coefficient Γ approaches 1).

  That is, the first impedance matching circuit 32 (including the first balun 40 as a parallel circuit provided between the first impedance matching circuit 32 and the first phase adjustment circuit 33) has a voltage reflection coefficient Γ in the vicinity of zero. And the impedance of ZoffT is changed so that the absolute value of the voltage reflection coefficient Γ becomes large.

  FIG. 17 shows the impedance at the output of the first phase adjustment circuit 33 (that is, the output of the transmission circuit 37, CX5 in FIG. 12). As described above, the first phase adjustment circuit 33 in the first embodiment includes the two-stage low-pass filter, and thereby shifts the signal phase of the transmission signal. As a result, the low-pass filter behaves in the same manner as a circuit in which a transmission line is added in series, and the impedance rotates on a circle centered on the R50 point. The shift amount of the signal phase is determined so as to rotate beyond this. More specifically, the first phase adjustment circuit 33 shifts the signal phase by 3 / 4λg with respect to the transmission signal (wavelength λg) propagating in the first substrate 59a, and as a result, the impedance is shown on the Smith chart. I make 1.5 laps. When only the phase adjustment function is provided, the first phase adjustment circuit 33 does not require a phase shift exceeding 1 / 2λg, but the attenuation characteristic is improved and the low-pass filter function (first phase adjustment circuit 33) ( In order to enhance the noise removal for the transmission signal and the prevention of noise mixing from the power supply line 45, it is desirable to shift the signal phase in this way. On the other hand, in terms of phase adjustment, the first phase adjustment circuit 33 is equivalent to shifting the signal phase by ¼λg, whereby the impedance of the transmission circuit 37 when the PA 31 is inactive is: After the transition from the vicinity of the R0 point before the transition, it moves to the vicinity of the R∞ point and becomes a high impedance state.

  In the above-described example, the initial impedance state of the PA 31 has been described with reference to FIG. 13, but the first impedance matching circuit 32 is in various states depending on the setting of the values of LI1, LI2, C1, and C2. The impedance can also be transited to the states of FIGS. 14 to 16 once via the state of FIG. As described above, in the first embodiment, the impedance of the transmission circuit 37 when the PA 31 is activated / deactivated is made to have an axisymmetric (ie, L / C property) relationship of the Smith chart, and thereafter It can be said that the impedance is changed according to the process described above.

  The configuration and operation of the first phase adjustment circuit 32 (including the first balun 40) and the first phase adjustment circuit 33 in the transmission circuit 37 have been described above in detail, but the impedance matching state and the high impedance are also applied to the reception circuit 38. The process of separating states is exactly the same. Therefore, although detailed description is omitted, the impedance of the reception circuit 38 viewed from the antenna 13 when the LNA 36 is activated is the impedance of the reception circuit 38 viewed from the antenna 13 when the ZNAR and LNA 36 are deactivated. As ZoffR, parameters constituting the circuit may be selected so as to have the same relationship as ZonT and ZoffT described above.

  FIG. 18A is an explanatory diagram showing the state of impedance viewed from the antenna when the PA is activated, and FIG. 18B is an explanatory diagram showing the state of impedance viewed from the antenna when the LNA is activated. .

  As shown in FIG. 18A, when the PA 31 is ON (and the LNA 36 is OFF), the output impedance of the transmission circuit 37 is matched with the antenna 13 and radio waves are emitted from the antenna 13, but the reception circuit 38 Is in a high impedance state, and the output of the transmission circuit 37 is prevented from flowing into the reception circuit 38.

  On the other hand, as shown in FIG. 18B, when PA 31 is OFF (and LNA 36 is ON), the output impedance of the transmission circuit 37 is in a high impedance state, and the input impedance of the reception circuit 38 is matched with the antenna 13. The radio wave received by the antenna 13 is sent only to the receiving circuit 38, and the transmitting circuit 37 is not affected at all.

  19A is an explanatory diagram for explaining a high impedance state on the Smith chart, FIG. 19B is an explanatory diagram showing a current flow in the high impedance state, and FIG. 19C is an equivalent circuit of FIG. 19B.

  Hereinafter, the high impedance state of the transmission circuit 37 and the reception circuit 38 will be described in detail with reference to FIGS. 19A, 19B, and 19C.

  As shown in FIG. 19A, in the first embodiment, 4Ω on the real axis of the Smith chart (however, the real axis value in FIG. 19A indicates the normalized impedance and is generally 50Ω. X4 times = point of 200 Ω, hereinafter referred to as R200 point), a range where the resistance is higher than 200Ω on the right side, that is, on the real axis, is in a high impedance state.

  FIG. 19B shows a state in which the output of the transmission circuit 37 and the impedance of the antenna 13 are matched, and the input of the reception circuit 38 is in a high impedance state. At this time, the output impedance Zs of the transmission circuit 37 and the impedance ZL1 of the antenna 13 are both 50Ω. On the other hand, the input of the receiving circuit 38 is in a high impedance state, and its input impedance ZL2 = 200Ω. At this time, as shown in FIG. 19B, the current i flows out from the transmission circuit 37, and this current is shunted as the current i1 to the antenna 13 and the current i2 to the reception circuit 38. This equivalent circuit is drawn as shown in FIG.

  For this equivalent circuit, the reflection loss is first evaluated. When the total resistance of the parallel circuit composed of ZL1 and ZL2 is expressed as ZL, the voltage reflection coefficient Γ is

Γ = (ZL−Zs) / (ZL + Zs) (Expression 3)
It is expressed. Here, since the total resistance ZL = 1 / (1/200 + 1/50) = 40Ω, the voltage reflection coefficient Γ when the high impedance state is 200Ω is

  Γ = (40−50) / (40 + 50) = − 0.11.

  The reflection loss RL is

RL = 1−Γ ² (Equation 4)
Is defined as

RL = 1-0.11 ² = 0.987, which corresponds to -0.05 dB.

  Next, the loss due to the diversion is calculated.

Assuming that the impedance ZL1 of the antenna 13 and the impedance ZL2 of the receiving circuit 38 are given, the current i1 flowing into the antenna 13 is {200 / (200 + 50)} i. here,
P = v × i1 (Equation 5) P = {200 / (200 + 50)} v × i1 = 0.8 v × i1
This corresponds to -0.97 dB.

  That is, it is understood that the total loss = reflection loss + diversion loss = −0.05−0.97 = −1.02 dB.

  FIG. 20 is a graph showing the relationship between the input impedance of the receiving circuit 38 and the total loss when the PA 31 is activated and the LNA 36 is deactivated.

  FIG. 20 is a graph of loss (total reflection loss and loss due to shunting) when the input impedance of the reception circuit 38 is changed with Zs = ZL1 = 50Ω fixed in FIG. Is. Conventionally, when an RF circuit is configured using an antenna switch module and discrete components, experience shows that there is no problem in sound quality in simultaneous transmission and reception if the loss is about −1.0 dB. Therefore, a loss of -1.0 dB is generally a design target for circuit design. Thus, it has been found that the design goal can also be achieved by the configuration of the first embodiment.

  In addition, according to the sensory evaluation and the like conducted by the inventors, the loss of -1.5 dB is considered to be an allowable loss because the sound quality and the like are deteriorated when the loss is greater than about -1.5 dB. . According to FIG. 20, the input impedance of the receiving circuit 38 at this time is about 112Ω.

  That is, when the PA 31 of the transmission circuit 37 or the LNA 36 of the reception circuit 38 is inactivated, the output impedance of the transmission circuit 37 or the input impedance of the reception circuit 38 is increased to the high impedance when viewed from the antenna 13. As a specific impedance value Z at the time of being applied, Z ≧ 112Ω as a minimum value (r = 2.24 times in comparison with 50Ω), preferably Z ≧ 200Ω (r = 4 times same) Is desirable.

  Thus, since ZonT is 50Ω, the first phase adjustment circuit 33 changes the phase of the transmission signal so that ZoffT> 2 × ZonT.

10 Signal processing unit 10e TDD / TDMA processor (control unit)
12 Radio part (RF part)
13 Antenna 30 Amplifier module 31 PA (power amplifier, first amplifier)
31a Final stage amplifier 32 First impedance matching circuit 33 First phase adjustment circuit 34 Second phase adjustment circuit 35 Second impedance matching circuit 36 LNA (low noise amplifier, second amplifier)
37 transmission circuit 38 reception circuit 39 connection point 39a first connection point 39b second connection point 40 first balun 41 second balun 45 power supply line (power supply)
46 DC cut capacitor 56 Open stub 59a First substrate 59b Second substrate 59c Third substrate 59d Fourth substrate 100 Master device 200 Slave device

Claims (13)

A first amplifier for amplifying a transmission signal;
A transmission circuit for processing the transmission signal amplified by the first amplifier;
An antenna for transmitting a transmission signal processed by the transmission circuit;
A receiving circuit for processing a received signal received by the antenna;
A second amplifier for amplifying the received signal processed by the receiving circuit;
A controller that alternately and exclusively activates the first amplifier and the second amplifier,
ZonT represents the impedance of the transmission circuit viewed from the antenna when the control unit activates the first amplifier, and the transmission circuit from the antenna when the control unit deactivates the first amplifier. ZonT is the impedance when the control unit is activating the second amplifier, ZonR is the impedance viewed from the antenna when the control unit is activating the second amplifier, and the control unit is deactivating the second amplifier. When ZoffR is the impedance of the receiving circuit viewed from the antenna when
The transmission circuit performs a first impedance matching that causes the ZonT and the ZoffT to transition so that the voltage reflection coefficient Γ of the ZonT is close to 0 and the absolute value of the voltage reflection coefficient Γ is increased. A circuit, and a first phase adjustment circuit that causes the ZoffT to transition to a high impedance state,
The receiving circuit performs second impedance matching to transition the ZonR and the ZoffR so that the voltage reflection coefficient Γ of the ZonR is close to 0 and the absolute value of the voltage reflection coefficient Γ of the ZoffR is increased. A wireless communication apparatus comprising: a circuit; and a second phase adjustment circuit that causes the ZoffT to transition to a high impedance state . The first impedance matching circuit includes a first capacitor;
2. The radio according to claim 1, wherein one end of the first capacitor is connected between the first amplifier and the first phase adjustment circuit, and the other end of the first capacitor is grounded. Communication device. The second impedance matching circuit includes a second capacitor;
The one end of the second capacitor is connected between the second amplifier and the second phase adjustment circuit, and the other end of the second capacitor is grounded. Any one of the radio | wireless communication apparatuses. The first phase adjustment circuit changes the phase of the transmission signal so that ZoffT> 2 × ZonT,
The radio communication apparatus according to claim 1, wherein the second phase adjustment circuit changes the phase of the reception signal so that ZoffR> 2 × ZonR. When the wavelength of the transmission signal in the transmission circuit is λg,
The wireless communication apparatus according to claim 1, wherein the first phase adjustment circuit changes the phase of the transmission signal to be larger than ½λg. The first impedance matching circuit, the first phase adjustment circuit, the second impedance matching circuit, and an inductor and a capacitor constituting the second phase adjustment circuit are formed by routing a wiring pattern . The wireless communication device according to any one of 5 . A first substrate on which the wiring pattern is formed;
A second and a third substrate on which a ground pattern is formed,
The wireless communication apparatus according to claim 6 , wherein the second substrate and the third substrate are provided on the front and back surfaces of the first substrate so that the ground pattern overlaps the wiring pattern. A fourth substrate on which the first amplifier and the second amplifier are mounted;
A via hole provided in the fourth substrate and the second or third substrate, electrically connecting the fourth substrate and the first substrate;
Through the via hole, a transmission signal amplified by the first amplifier is supplied to said transmission circuit, according to claim 7, wherein the supplying the reception signal received by the antenna to the second amplifier Wireless communication device. A plurality of via holes connecting the second substrate and the third substrate;
8. The wireless communication apparatus according to claim 7 , wherein the via hole group is provided so as to surround the transmission circuit and the reception circuit in the first substrate sandwiched between the second substrate and the third substrate. . The first phase adjustment circuit is composed of two first and second stage low pass filters connected in series, and one of the capacitors arranged at the end of the first stage and the start of the second stage is one The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is shared by a capacitor. The output of the first amplifier is a differential output signal,
In the transmission circuit, a first balun that converts the differential output signal into a single-ended signal is provided between the first impedance matching circuit and the first phase adjustment circuit.
The said 1st balun includes the parallel circuit which changes an impedance so that the absolute value of voltage reflection coefficient (GAMMA) may become large when the said 1st amplifier is deactivated, The any one of Claims 1-10 characterized by the above-mentioned. The wireless communication device described. The input of the second amplifier is a differential input signal,
In the receiving circuit, a second balun for converting the single-ended input into a differential input is provided between the second impedance matching circuit and the second phase adjusting circuit,
The second balun is in any of the preceding claims, characterized in that it comprises a parallel circuit for shifting the impedance such that the absolute value of the voltage reflection coefficient Γ is increased when the deactivation of the second amplifier The wireless communication device described. The wireless communications apparatus of claim 1 2, wherein the configuring the second balun resonator having a band-pass filter characteristics.

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